Stereoisomeric effects in thermo‐remendable polymer networks based on Diels–Alder crosslink reactions

Abstract

This study describes the synthesis, the spectroscopic, and the thermal characterization of linear and crosslinked polymers as well as a number of corresponding model compounds, containing Diels–Alder adducts derived from furan and maleimide groups. The thermal reversibility (rDA, DA) of structurally varied model compounds, polymeric and network structures were studied by differential scanning calorimetry, where possible in combination with 1H NMR spectroscopy. It was established that the endo and exo DA stereoisomers show significantly different thermal responses: the rDA of the endo DA‐adducts typically takes place at 20–40 K lower temperatures than that of the corresponding exo DA‐adducts in all cases, with the exception of some aromatic maleimides. Although in situ isomerization was observed to a limited extent and only in some cases, this effect is not expected to influence the thermoremendability of DA‐crosslinked networks being dependent on two separate stereoisomeric rDA steps. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3456–3467, 2010

Characterization and kinetic study of Diels-Alder reaction: Detailed study on N-phenylmaleimide and furan based benzoxazine with potential self-healing application

“…While the endo compound is kinetically favoured, the exo is thermodynamically favoured and thus more stable [5,6]. The aim of the detailed study of the thermal behaviour of the PMI/ GF mixture is its possible further application as a self-healing polymer network.…”

“…DA adduct is the mixture of two diastereomers called endo and exo adducts. Temperature of the rDA reaction leading to the appearance of the endo adduct is typically lower than that of the exo adduct [5,6]. Due to the thermal reversibility of DA reactions, they are frequently applied in the production of remendable and recyclable materials [7][8][9][10].…”

“…On the other hand there might be a reason, why there is not yet a known self-remendable benzoxazine polymer material with DA reaction based remendability. The reason being high curing temperature needed for polymerization of benzoxazines [31,32], usually quite above the temperature of rDA reaction (~100°C) of normally used diene and dienophile system (furan and maleimide) [5,6]. This means that DA connections are broken and starting compounds are formed.…”

High-performance hybrid materials prepared by the thermo-reversible Diels–Alder polymerization of furfuryl ester-terminated butylene succinate oligomers and maleimide compounds

“…The process and kinetics of chemical recycling via thermo-reversible Diels-Alder (DA) reactions between furan and maleimide (MI) have been widely studied. [19][20][21][22][23][24][25] Yoshie and co-workers reported the synthesis of a readily recyclable DA adduct of telechelic furfurylamide-terminated PBS and 1,2-bis (maleimide)ethane. 24 Chujo and co-workers reported the synthesis of organic-inorganic polymer hybrids by the sol-gel reaction of tetraethoxysilane in the presence of poly(furfuryloxymethylstyrene-co-styrene) and maleimidemethyl 3-(triethoxysilyl)propylcarbamate (MTES).…”

Investigation on the thermal properties of new thermo-reversible networks based on poly(vinyl furfural) and multifunctional maleimide compounds

“…Thermallyreversible DA reactions have been used in numerous studies including polymer synthesis from multifunctional monomers [4,[7][8][9][10][11][12][13][14][15] or by cross-linking of functional copolymers containing maleimide or furan pendant groups [16][17][18][19][20][21][22], surface modifications [16,23], organic-inorganic polymer hybrids [24,25], reversible crosslinking polymer chains/ gels [5,16,24,26] and remendable/self-healing polymers [11,12,27]. Due to the fact that these reactions can proceed under mild conditions without a catalyst, this makes them attractive for designing covalently reversible bonds in which furan and maleimide functional groups are responsible for association and dissociation [28][29][30][31]. In this study, we report the preparation and characterization of thermo-reversible networks based on poly(vinyl furfural) and multifunctional maleimide compounds, as the basis for obtaining asymmetric membranes by the phase inversion method.…”